With diplomacy stalled, the bloodletting in the Syrian city of Homs continues. ITN's John Ray reports.

The report said the Pentagon’s Central Command has begun a preliminary review of U.S. military capabilities in the region, which one senior official called a “scoping exercise” that would provide options for Barack Obama if necessary.

“The decision-makers have not determined we are at a point of no return,” the senior official was quoted as saying. “There is still a window, it is just that that window is closing," the official said, adding that "nothing is off the table."

“We definitely don’t want to militarize the situation. If it’s avoidable, we are going to avoid it. But increasingly it looks like it may not be avoidable,” the official if reported to have said.

President Assad's British-born wife, Asma, has sent an email in support of her husband. ITN's Daisy McAndrew reports.

Observers agree that outright Western military intervention in Syria is unlikely as such a mission would be more difficult and risky than last year's operation in Libya. Its complex geography and ethnic mix make the removal of President Bashar Assad's regime difficult, and one option could be to arm rebel groups such as the Free Syrian Army.

While the West and Arab allies discuss options, the humanitarian crisis inside Syria has worsened, with hundreds of rebels killed in recent days in the city of Homs. Assad's army fired mortars and rockets Thursday, the latest salvo in a weeklong bombardment aimed at crushing pockets of dissent.

The United Nations chief on Thursday condemned the ferocity of the government assault on Homs. "I fear that the appalling brutality we are witnessing in Homs, with heavy weapons firing into civilian neighborhoods, is a grim harbinger of things to come," U.N. Secretary General Ban Ki-moon said after briefing the Security Council in New York.

Activists and residents report hundreds of people killed over the last week as Assad's forces try stamp out opposition in Homs and as Thursday dawned, rocket and mortar fire rained down again on Baba Amro, Khalidiya and other districts. Armored government reinforcements also poured into the eastern city.

The Syrian Revolution Coordinating Commission said at least 30 civilians in Homs were killed in bombardments on Thursday morning on mainly Sunni Muslim neighborhoods that have been the focus of attacks by the government forces led largely by members of Assad's Alawite religious minority.

Such sectarian divisions have been coming to the surface as killings have increased on either side of the conflict.

The main street in Baba Amro was strewn with rubble and at least one house was destroyed, according to YouTube footage broadcast by activists from the district who said troops had used anti-aircraft cannon to demolish the building.

The video showed a youth putting two bodies wrapped in blankets in a truck. What appeared to be body parts were shown inside the house.

Hussein Nader, an activist in Baba Amro, told Reuters: "Silence reigns for four to five minutes, then another barrage of tank fire or rockets or mortar rounds comes in."

"Whole houses have come down and we do not know how many more have been killed. They are not advancing and it seems that they are content by continuing to shell Baba Amro until every inhabitant is killed."

The U.N. estimates that 5,400 people have been killed in Syria since the uprising agains Assad began in March 2011. But that figure is from January, when the U.N. stopped counting because deteriorating security prevented verification of the figures.

The White House said it was talking to allies about holding a “Friends of Syria” meeting in the near future and was considering delivering humanitarian aid to affected areas in the country.

“We are, of course, looking at humanitarian assistance to the Syrian people, and we have for some time. We’re consulting with our international partners, and we anticipate this being one of the focuses of the discussions that we’ll have,” Jay Carney, the White House press secretary, said, according to the Telegraph.

Influential figures in Washington have recommended setting up a “humanitarian corridor” or safe haven, while others, such as Senator John McCain, have said it was time to consider arming the rebels of the Free Syrian Army.

U.N. Secretary-General Ban Ki-moon said on Wednesday the Arab League chief told him he intends to revive an Arab League monitoring mission in Syria, which has collapsed amid continuing violence there.

The U.N. chief provided no specifics, but the idea appears aimed at giving the regional group a boost after the league's earlier mission was pulled out of the country because of security concerns.

"In the coming days we will further consult with the council before fleshing out details," Ban said. "We stand ready to assist in any way that will contribute toward improvement on the ground."

Ban also reiterated his "deep regret" over the council's inability to speak in one voice to stop the bloodshed. Russia and China used their veto powers on Saturday to block a Security Council resolution backing an Arab League peace plan that calls for Assad to step aside.

U.S. Secretary of State Hillary Rodham Clinton expessed fury after Saturday's veto by Russia and China at the United Nations blocking action against the continuing violence in Syria, describing it as "a travesty."

Libya has given Syria's charge d'affaires and his staff in Tripoli 72 hours to leave the country, the foreign ministry said in a statement on Thursday.

Libya's National Transitional Council (NTC) officially recognised the Syrian opposition council in October as the legitimate authority in Syria after months of unrest against President Bashar al Assad.

Germany said on Thursday it is expelling four Syrian diplomats following the arrest earlier this week of two men accused of spying on Syrian opposition groups in Germany.